1. Field of the Invention
The invention relates to a perpendicular magnetic write head provided with a magnetic pole and a trailing shield, and to a magnetic recording device using the perpendicular magnetic write head.
2. Description of Related Art
In recent years, along with an increased surface recording density in a magnetic recording medium (hereinafter, referred to as a “recording medium”) such as a hard disk, improvement in performance of a magnetic write head is desired.
Therefore, as a recording system of a magnetic write head, a perpendicular magnetic recording system in which a direction of a signal magnetic field is set to a direction intersecting a recording surface of a recording medium attracts attention, in place of a longitudinal magnetic recording system in which a direction of a signal magnetic field is set to an in-plane direction of a recording surface. This is because a high linear recording density is obtainable and a recording medium in which information has been recorded is difficult to be affected by thermal fluctuation.
A magnetic write head of the perpendicular magnetic recording system (hereinafter, referred to as a “perpendicular magnetic write head”) includes a main magnetic pole layer that guides magnetic flux generated in a thin film coil to a recording medium, and the main magnetic pole layer includes a front end section (a magnetic pole) that has a small width and generates a recording-use magnetic field (a perpendicular magnetic field). The configuration of the perpendicular magnetic write head has been variously studied in order to improve recording performance.
Specifically, a trailing shield is provided on a trailing side of the main magnetic pole layer with a non-magnetic gap layer in between (for example, Japanese Unexamined Patent Application Publication No. 2006-134507).
If the trailing shield is used, when magnetic flux concentrated on the front end section of the main magnetic pole layer is released toward the recording medium, a part of the magnetic flux is taken into the trailing shield, and thus magnetic field gradient of perpendicular magnetic field is increased. In addition, since, when the magnetic flux emitted from the main magnetic pole layer returns to the perpendicular magnetic write head through the recording medium, the magnetic flux is easily taken into the trailing shield, spread of the magnetic flux in a recording track width direction is suppressed. As a result, occurrence of erasure in adjacent tracks, namely, a defect in which information recorded in tracks adjacent to a track to be recorded is unintentionally erased is suppressed.
However, when the magnetic flux concentrated on the front end section of the main magnetic pole layer is excessively taken into the trailing shield, the amount of the magnetic flux released from the front end section is decreased, and the magnetic field intensity of the perpendicular magnetic field is accordingly decreased. Therefore, relationship of so-called trade off is established between securement of the magnetic field intensity of the perpendicular magnetic field and suppression of occurrence of erasure in adjacent tracks.
Accordingly, it is strongly desirable to achieve both securement of magnetic field intensity of perpendicular magnetic field and suppression of occurrence of erasure in adjacent tracks.